BUG #14484: ERROR: missing chunk number 0 for toast value

The following bug has been logged on the website:

Bug reference: 14484
Logged by: Marc Mamin
Email address: marc(at)intershop(dot)de
PostgreSQL version: 9.6.1
Operating system: Linux 3.7.10-1.45-default #1 SMP Tue Dec 16 20:27:
Description:

According to the mailing lists this seems to be a bug that is though to be
fixed...

I got this error once during manual vacuum while evaluating deletion of old
toasted value by replacing them with a short text.

For this, I have alternated bunch insertions of large values with updates of
older one:

UPDATE mytable set msg='deleted'
FROM (
SELECT id
FROM mytable
WHERE t < now() - interval '10d'
AND msg <> 'deleted'
LIMIT 1000
)todel
WHERE mytable.id=todel.id

after a while I got the error during a vacuum full:

vacuum (full, analyze ,verbose)mytable
ERROR: missing chunk number 0 for toast value 442005 in pg_toast_397983
SQL state: XX000

as suggested here I could fix it with an analyze of that table:
https://www.postgresql.org/message-id/CAL7VFcJYBiVLjAiXqwdAWw9noeef2tM0bj-%3Dw_2um6b6RacA6Q%40mail.gmail.com

I couldn't reproduce it though.

best regards,
Marc Mamin